With Vipers Rage, does this affect all characters controlled by the target player for the rest of the phase, including any new characters added to play after the event card has been played?

"After you lose a challenge ... all characters controlled by the attacker lose ... icons .. until the end of the phase"

Same question re Only Game That Matters - "Until the end of the challenge, participating characters without an intrigue icon do not count their STR"

Presumably someone added to the challenge after the event card has been played would be subjected to the same effect

I can't spot any difference between these two events, in terms of structure, but ran into a dispute about Vipers Rage last night (I assume both effects is continuous for the stated duration)

thanks

You are correct that Viper's Rage is both general and un-targeted. As such, it will be applied to characters that enter play over the course of its duration.

Yes - that is correct but was the point being disputed

The event applies a constant affect, so all characters are checked and have modifiers applied continuously - what was around / active when the event card was played is irrelevent

Technically, they are lasting effects, not constant effects, but the difference is largely irrelevant here. (They act the same, tend to be applied the same, but a constant effect depends on the presence of the card that creates it while a lasting effect is created by a triggered or passive effect and continues through its duration regardless of what happens to the card that created it.)

It is the lack of choosing targets that makes these effects generally applicable and allows them to be applied to characters over the course of the effect's duration, whether they were there when the effect was created or not.